Solder connecting apparatus



May 12, 1942. R. G. HUMPHREY 2,283,153

SOLDER CONNECTING APPARATUS Filed D80. 51, 1940 7 Sheets-Sheet 1 260 /52 casrsn RHEO. /59 v /4 6? 257 -rHRMosmr CASTER TIMER i INVENTOR 245 R. G. HUMPHREV ATTORALEY' May 12, 1942. v R. e. HUMPHREY SOLDER CONNECTING APPARATUS 7 Sheets-Sheet 2 Filed Dec. 51. 1940 INVENTOR. By R. a. HUMPHREV XWM ATTORNEY May 12, I942. R. e. HUMPHREY SOL DER CONNECTING APPARATUS Filed Dec. 31, 1940 '7 Sheets-Sheet 3 lA/VENTOR y 1942- R. a. HUMPHREY 2,283,158

SOLDER CO NNECTI N G APPARATUS Fil ed Dec 31, 1940 7 Sheets-Sheet 4 Wyn/m R. G. HUMPHRE V Q19. %6QQA A TTORNEV May 12, 1942. R. e. HUMPHREY SOLDER CONNECTING APPARATUS 7 Sheets$heet 5 Filed Dec. 31, 1940 ATTORAZIL) May 12, 1942. R. e. HUMPHREY SOLDER CONNECTING APPARATUS 7 Sheets-Sheet 7 Filed Dec. 31, 1940 INVENTOR R. G. HUMPHREV ATTORNEY Patented May 1 2, 19 42 r UNITED STATES PATENT OFFICE SOLDER CONNECTING APPARATUS Robert G. Humphrey, Pelham, N. Y., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application December 31, 1940, Serial No. 372,528

This invention relates to electrowelding ap- 2 Claims.

paratus for and a method of securing a wire of relatively fine gauge to a metal surface.

The invention is applicable to the securing of wires of relatively fine gauge to metal surfaces formed on piezoelectric crystals.

In accordance with this invention a pellet of solder of predetermined size and form is cast on an end of the wire, the pellet is then placed in contact with a suitably prepared metal surface on a crystal element, and a solder connection is then made to electrically connect the wire to the metal surface.

When the invention is used in connecting wires to crystal elements the solder connections made are of such form and character that the wires may be used not only as lead-in wires for the crystal elements but also as supporting means for the crystals.

The invention provides a method of and apparatus for accurately and rapidly making entirely satisfactory solder connections between wires of very fine gauge and the electrode surfaces of piezoelectric quartz crystals.

In the drawings:

Fig. 1 is a top and front view in perspective of a support with the apparatus mounted in required positions;

Fig. 2 is a schematic diagram of some of the apparatus involved;

Fig. 3 is a top View of a portion of the support and a chuck for holding the wire in required positions during practice of the invention and is drawn on an enlarged scale relative to Fig. 1;

Fig. 4 is a side View, partly in section, of Fig. 3;

Fig. 5 is a detail part shown in Figs. 3 and 4;

Fig. 6 is an end view of Fig. 5;

Figs. 7 and 8 are top views of jaws of the chuck, each view showing the jaws in a different position and being enlarged relative to Fig. 3;

Fig. 9 is a side elevational View of Fig. 8 and having a wire supported in the jaws;

Fig. 10 is an end view, in section, of Fig. 9 taken on the line U Fig. 11 is a top view of the solder pellet caster device enlarged relative to Fig. 1;

Fig. 12 is a view in section of parts shown in Fig. 11 and taken on the line |2|2;

Fig. 13 is a front view, in section, of Fig. 11 and taken on the line |3--| 3;

Fig. 14 is a View corresponding in general to Fig. 11 but with certain of the parts operated to different positions;

Fig. 15 is a front view, in section of Fig. 14 and taken on the line ||5 Fig. 16 is a greatly enlarged view of a portion of Fig. 11 and shows a crucible employed in the device shown in that figure;

Fig. 17 is a front view, in section, of Fig. 16 and taken on the line Fig. 18 is a side view, partly in section, of parts shown in Fig. 17, taken on the line |8|8 and showing also a wire and a solder pellet cast in the crucible and a pressure button inserted in the crucible;

Fig. 19 is an enlarged view of a portion of the wir and the solder pellet cast on the wire;

Fig. 20 is a top plan View, partly in section, of a hot plate equipped with means for adjusting and holding the crystal in required position;

Fig. 21 is a front view, partly in section, of Fig. 20 taken on the line 2|-2|;

Fig. 22 is a view, in section, taken on the line 22-42 in Fig. 20;

Fig. 23 is .a side view, in section, of Fig. 21

taken on the line 23-23; and

Fig. 24 is a view, partly in section, of the hot plate and a portion of the support and taken from beneath the support.

The solder pellet caster device is covered in a divisional application of this case, Serial No. 434,573, filed March 13, 1942, and the hot plate device is covered in a divisional application of this case, Serial No. 434,574, filed March 13, 1942.

Referring to Fig. 1 the support 3| comprises a U shaped top 32 with downwardly extending walls 33 and 34. On the top 32 are mounted manually operated switches 35, 36, 31 and 38, an ammeter 39 and plug receptacles 4B and 4| to receive electrical supply lines 42 and 43. Manually operated control knobs 44 and 45 are mounted on shafts not shown but which extend through the respective wall members 33 and 34. Set within the space defined by the inner portion of the top 32 and resting on ledges 46 formed thereon is a slab 41 of suitable insulating material on which are mounted the caster device 48, the chuck 49, the hot plate device 5|] and a reel support 5|. I The various devices by means of which the wire connections are made are so arranged and mounted on the support 3| and the slab 4'! that the wire connections can be made in a rapid and accurate manner. The reel support 5| comprises a post 52 secured at its lower end in a flange 53 suitably mounted on the slab by means of screws 54. The upper portion of the post 52 is bent to provide an axle 55 on which is rotatably supported the reel 56 containing a supply of Wire 51, the reel 56 being retained against accidental dislodgement from the axle 55 by means of a crosspin 58. The wire 51 is led downward from the reel 56 to the chuck 49.

To enable a complete understanding of the invention a detail description of the devices employed in making the wire connections is given under separate headings.

Chuck The chuck 49 is designed to receive and hold in a required position an end portion of the wire 51 preparatory to and while the end of the wire is being connected to the electrode surface on a crystal element. The chuck 49 as shown in Figs. 1 to comprises an arm 59 supported on the under-side of which are jaws 69-43 I and an electromagnet 62. The jaw 6| is maintained in a fixed position by means of the headed pin 63 and the screw 64, which extends through apertures in the arm 59. The jaw 69 is pivotally supported by means of the headed pin 65 which extends through an aperture in the arm 59 and into the jaw 69 near the gripping end of the jaw. The other end of the jaw 69 is extended to the portion of the 'electromagnet 62 and is connected to the armature 69 thereof by means of a rod 61. A retracting spring 68 is provided to normally maintain the jaws 69 and BI in an open condition, the spring 68 being secured at one end to the jaw 69 and having its other end held by an apertured plate 69. When an end of the wire 51 is inserted between the gripping ends of the jaws 99 and BI and the electromagnet 62 is energized to attract its armature 66 the jaw 69 is operated to move its gripping end toward the corresponding end of jaw 6| to clamp the wire between the jaws and thus hold the wire in a required position. When the electromagnet 92 is deenergized the spring 68 moves the jaw 69 back to normal position to release the wire 51. A switch 19 is insulatingly mounted on the arm 59 to control the operation of the electromagnet 62, which is supplied with operating current from a source H over an obvious circuit shown in Fig. 2 including the conductors 12 and 13. The arm 59 is made of conducting material and carries a contact finger 14 which is insulatingly supported on the arm and extends below the gripping ends of the jaws and is secured at one end in a pileup 15 mounted on the under-side of the arm by means of the screws 16. The pile-up 15 contains the plate 69 which may be made of insulating material or be suitably insulated from the finger 14 and the arm 59. The arm 59 is electrically connected to one side of the source of current supply II by the conductors 13 and 11. The function of the contact finger 14 will be subsequently explained.

The arm 59 is apertured to receive an upper end portion of an upright rotatable shaft 18 and rests on a flanged collar 19 which is secured to the upper portion of the shaft 18 by means of the screws 89. The shaft 18 is journaled in a bearing 8| supported in an aperture in the slab 41, the bearing 8I being equipped with an upper flange and having a male threaded lower end to receive a nut and washer 82 so that the bearing is clamped in position in the slab 41. The shaft 18 is also journaled in a lower bearing 83 supported in an apertured plate 84 located below the slab 41, the plate 84 being supported by means of screws 85 on the lower ends of pillars 86 which extend downwardly from the slab 41, the upper ends of the pillars being held by screws 81 extending through the slab 41. The upper end of the shaft 18 is equipped with a manually operated knob 88 by means of which the arm 59 may be rotated and also lifted relative to the slab 41, the shaft 18 being rotatable and also longitudinally slidable within the bearings BI and 83. A counter-weight device 89 is provided to lend a partial lifting effect to the shaft 18 and the arm 59 so that the weight of these parts and the apparatus supported on the arm 59 will not be such as to create too great a pressure on a wire held in the jaws and the parts or elements upon which the end of the wire is rested. The counter-weight device 89 comprises a lever 99 fulcrumed in a bracket 9| supported on and extending below the plate 84. A weight 92 is ad justably supported on one end of the lever 99 and the unweighted end of the lever 99 bears upwardly against the lowermost end of the shaft 18. The weight 92 is adjusted so that its effect will not be quite sufiicient to raise the shaft 18 and the arm 59 from the position shown in Fig. 4. Supported on the upper surface of the plate 84 are two positioning pins 93 and 94 and a U- shaped bracket 95, the bracket 95 serving as a support for a wheel 99. The pins 93, 94 and the wheel 96 serve in cooperation with a flat bar 91 to hold the shaft 18 and the arm 59 in two definite positions of rotation. The bar 91 is apertured near one end to receive the shaft 18 and is provided with a collar 98 which is secured to the shaft 19 by means of set screws 99. Notches I99 and I9I are provided in the bar 91 to receive the wheel 96 and an aperture I92 is provided in the bar 91 to receive the pin 93 when the bar is in one position and the pin 94 when the bar is rotated to another position. To prevent undue rotational movement of the arm 59 two spring fingers I93 and I94 are mounted on the slab 41 to frictionally engage the sides of a longitudinally split cylinder I95 which is clamped in place about the shaft 18 by means of the set screws I96.

A tapered shell I91 is mounted on the free end of the jaw BI by means of pins I98 and a screw I99, the shell I91 being apertured to receive the pins I98 and the screw I99. It will be seen in Fig. 10 that the shell I91 extends down one side of the jaw 6| and across the upper and lower portions of the jaws 69 and 6| and that a large aperture H9 is provided in the upper portion of the shell to permit extending of the wire 51 to the jaws 99 and BI and that a cone-shaped aperture IiI is provided in the lower portion of the shell I91. A button II2 made of material to which solder will not adhere is supported within the aperture I I I. The button H2 is shaped on its upper portion to fit the aperture III and has a lower reduced end portion II3 extending below the shell I91. The button II2 may be made of aluminum oxide or of some other material found suitable for the purpose and is longitudinally bored to slidably receive the wire 51. The function of the button I I2 is important as will be subsequently pointed out.

Caster device The caster device 48 is used to cast a pellet of solder on the end of the wire 51 and as shown in Figs. 11 through 18 comprises a crucible II4, a reservoir II5 for holding a supply of solder paste H9 and a plunger M1 for forcing the solder paste II6 into the crucible H4. The reservoir II5 comprises a block II8 of metal or other suitable material, longitudinally bored at II9 to receive the plunger II1 which projects into one end of the bore H9. The other end of the bore II9 isclosed by means of a relatively long plug I which is held in place by means of a screw I2! extending through an apertured end plate I22. The inner end of the plug I20 is shaped at I23 to provide a dished inclined surface. The top of the block I I8 is longitudinally slotted and milled out to provide a dovetail track I24 as shown in Fig. 12 to slidably receive a slide bar I25 having a conica1 aperture I26 formed therein which may be brought into register with an aperture I 2'! in the base of the dovetail track I24, the aperture I21 having communication with the reservoir H5. The block H8 is mounted by means of screws I28 on an apertured base plate I29 resting on the slab 41 and secured thereto by means of the screws I30 and a screw holding plate I3I.

The slide bar I25 is frictionally engaged at one end by the enlarged head portion I32 of a stud I33, the male-threaded lower end of which is mounted on a manually operated lever I34. The lever I34 is pivotally supported at one end by means of a screw I35 which extendsupwardly into an overhanging flange I36 integral with the end plate I22. The flange I35 is provided with an elongated curved aperture I31 designed to accommodate movement of the head portion I32 of the stud I33. The slide bar. I25 may be longitudinally moved by operation of the lever I34 and relative to the crucible I I4 which is supported in a fixed position as will be subsequently explained. A'disc I30 of quartz or other suitable material is mounted in the upper surface of the slide bar i215, the slide bar being suitably recessed to receive the disc and the upper surface of the disc being flush with the upper surface of the slide bar. The disc I38 is of larger diameter than the crucible H4 and serves as a removable closure for the bottom of the crucible I'I4. A small block I39 is mounted by means of a screw I40 on the upper surface of the slide bar I25 and is undercut to provide an overhanging portion I4I which serves as a removable top closure for the top of the crucible II4. A helical spring I42 is provided to bring the slide bar I25 back to normal position, the spring I42 being attached at one end to a pin I43 supported on the slide bar I25 and being secured at the other end to a pin I 44 mounted on a tab portion I45 of a bridge plate I46, the bridge plate I46 being disposed across the slide bar I25 and secured by means of screws !41 to the top of the block H8.

The crucible I I4 is electrically heated and comprises a ring I48 made of material suitable for transmitting heat to the solder paste in the crucible and for holding the solder when the solder is in a molten condition. I have found that stainless steel may well be used as the material for the ring I48. The ring I48 has an internal diameter about equal to the diameter of the solder pellet it is desired to cast and is frictionally held in the closed end portion I49 of a U-shaped bar I50. of electrical resistance material. A suitable material for the bar I50 is a nickel-chromium composition known to the trade as Nichrome. The two leg portions I5I-I52 of the bar I50 are connected to a suitable source of current supply to heat the bar I59 to a sufficient temperature to melt solder paste in the crucible I I4, the heat being transmitted through the ring I48 to the solderpaste. The ring I 43 may be made of electrical insulating material to prevent the electrical current from passing through the ring to the solder paste held therein; It may be made,

shown in Figs. 17, 18 and 12 is supported in an insulating block I55 and rests on an insulating strip I50, the block I55 and the strip I56 being mounted on the upper surface of the block I I8 by means of screws I51. Spaced electrodes I58 and i59 are supported in the insulating block I55 and in electrical contact with the leg portions I5I and I52 respectively of the bar I50 to carry current to the bar I50, the electrodes I 58 and I59 extending outwardly of the block I55 a sufficient distance to permit connection to a suitable source of current supply. An insulating strip IE0 is mounted on the block II8 across from the insulating strip I56. The strip I30 may be cemented or otherwise secured to the block H3 and serves as an insulating rest for the contact finger I4 on the chuck 49- when the chuck is being used over the caster device 48.

The plunger H1 is equipped with a manually operated lever I6I which is pivotally supported at one end on a pin I62 which extends throughthe lever I6I and through one end of a link I53, the other end of thelink I63 being pivotally supported on a pin I64 mounted on the under surface of the overhanging flange I35 of the end plate I22, the end plate I22 being secured to the block IE5 by means of screws I65 and being apertured at I66 to accommodate an end portion of the link I53. The lever I6I extends through a recess I01 in the outer end of the plunger It? and is pivotally supported therein by means of a rivet I00.

The caster device 48 in cooperation with the chuck 49 is used in casting a pellet of solder of predetermined size and form on the end of the wire 51. Fig. 19 shows the pellet H59 cast on the end of the wire 51. The size and form of the pellet I69 are controlled by the internal dimensions of the crucible II4, the amount of solder paste projected therein and the extent to which the reduced end portion II3 of the button H2 is inserted in the crucible I I4.

In order to fill the crucible II4 with the solder paste II6 the slide bar I25 is moved by means of lever I34 from the position shown in Figs. 11 and 13 to the position shown in Fig. 15, the head por tion I 32 of the stud I 33 serving to transmit move ment of the lever I34 to the slide bar I25. In this operation the spring I42 is elongated to provide suflicient spring tension to restore the slide bar I25 to its former position when the lever I34 is released. In the position shown in Fig. 15 the disc I38 has been removed from the bottom of the crucible H4 and the conical aperture I26 in the slide bar I25 is in register with the aperture I21 in the block II 3 and is in register with the crucible H4. The overhanging portion I4I of the block I39 is over the crucible II4 to close the top of the crucible. While the slide bar I25 is in this position thelever I5I is operated to move the plunger Il'I from the position shown in Fig. 13 to the position shown in Fig. 15. In this movement solder paste I I 6 is forced from the reservoir H5 upwardly through the aperture I21 and the conical aperture I26 and into the crucible II4, emergence of the solder paste from the top of the crucible II4 being prevented by the overhanging portion I4I of the block- I39. The levers I34 and I6I are then in the positions shown in Fig, 14. Since the stud I33 has reached one end of the slot I31 further movement of the lever I34 in this direction is prevented;

When the lever I34 is manually released the spring I42 returns the slide bar I25 and the lever I34 back to the normal position shown in Figs. 11 and 13. In this position the block I39 is away from the crucible I I4 so that the overhanging portion MI is no longer over the top of the crucible. The disc I38 is directly under the crucible I I4 and serves as a bottom for the crucible which is filled with the required amount of solder paste II6 for making the pellet I69. A screw I equipped with a lock nut I1I is adjustably supported in the outer end of the overhanging portion I36 of the end plate I22 and may be turned to project into one end of the slot I31 to limit the return movement of the lever I34 and the slide bar I25 and so that the disc I38 will be directly under the crucible I I4.

Hot plate device The hot plate device 50 is used to heat a crystal element to a required temperature and to hold the crystal in a required position while a wire is being solder-connected to a metallized surface on the crystal element, the crystal being heated to a temperature slightly below the melting point of the solder to reduce reaction of the crystal when a melting temperature is applied to the point at which the solder connection is being made.

As shown in Fig. 1 the hot plate device 50 is mounted on the slab 41 in such position that the chuck 59 may be rotated thereover. In this figure a crystal element I12 is supported on the hot plate device 50 in a position to have an end of the wire 51 solder-connected to a stripe I13 of solder on the crystal element. The crystal element I12 may be of any desired size and form and may be made of any required material. It will be assumed, however, merely for the purpose of explaining the invention that the crystal comprises a rectangular slab of quartz coated on its upper and lower major plane surfaces with metal as shown at I14. The metal coatings I14 serve as electrodes for the quartz crystal and may be for instance coatings of silver or other suitable material applied to the crystal, for example, by sputtering or by an evaporation process. The stripe I13 is shown as being located at a nodal point of the crystal but may be located at any other desired point, the point of location being determined by the particular character and form of the crystal and the use required. In piezoelectric crys tals of the form shown, however, it is advantageous to have the wire connected at the nodal point since the mechanical load of the wire and the metal stripe on the crystal would then be at the lowest point of oscillation. For the purpose of illustration and not in the sense of limiting the invention it will be assumed that the stripe I13 is a stripe of silver solder applied by any suitable means and manner across the flat plane surface of the crystal at the nodal point of the crystal.

The hot plate device 50 comprises a round table 115 and a rectangular frame plate I16 which is apertured to accommodate the table I15, the table I and the frame plate I16 being supported so that their upper surfaces are elevated relative to the slab 41.

The table I15 and the frame plate sesame I16 are adjustably mounted on a frame structure I11 supported on the under surface of the slab 41 and so that the table and frame may be moved as a whole backward and forward across a portion of the slab 41. As shown in Fig. 24 the slab 41 is provided with a relatively large oval aperture I18 to accommodate the table I15 which is relatively thick. The table I15 is made of suitable heat transmitting material, such, for instance, as aluminum or an aluminum composition and extends downwardly Within the aperture I18. The frame structure I11 comprises the bars I19, I and the track rods I8I and I82, the bars I19 and I80 being secured to the under surface of the slab 41 by means of the screws I83 and the track rods I8I and I82 being secured at their ends to end portions of the bars I19, I80 by means of the screws I84. Cross-bars I85, I86 are mounted on the under surface of the table I15 by means of the screws I81 extending through spacers I88 and rest on the track rods I8I, I82, and crossbars I-I86 being grooved at I89 to receive the track rods. Leaf springs I90 mounted on the under surfaces of the cross-bars I85, I86 by means of the'screws I9I extend into frictional engagement with the under portions of the track rods IBI, I82 to hold the table I15 against undue lifting movements relative to the track rods. A rotatable shaft I92 equipped with a manually operable knob I93 is provided to move the table and the frame plate as a whole relative to the slab 41, the shaft I92 being journaled in a bearing I94 in the bar I19 and being journaled in the cross-bar I 85 and having screw-threaded engagement with a female threaded aperture in the cross-bar I86. The round table I15 is equipped with cartridge type electrical heating elements I95 which are located in apertures I96 provided in the round table. A thermostat I91 is mounted in a slot I98 provided in the under surface of the table I15 to automatically control the operation of the heating elements I95. The thermostat I91 comprises a movable bimetallic contact finger I99 and a fixed contact strip 200 mounted at one end in a pile-up 20I, which is mounted on a rectangular mounting strip 202 supported by means of screw 203 in the slot I98. An insulating strip 204 is interposed between the fixed contact strip 200 and the mounting strip 202. The bimetallic contact finger I99 normally rests against an adjustable back stop 205 supported at one end in the pileup 20I and having its other end supported in a nut 206 mounted on a screw 201 supported in the table I 15. Turning of the screw 201 will cause adjustment of the bimetallic contact finger I99 relative to the fixed contact strip 200. An elongated aperture 208 is provided in the table I15 to accommodate wires after they have been attached to the crystal element and while other wires are being attached to the opposite face of the crystal element the aperture 208 extending from an outer edge of the table I15 and more than half the distance across the table I15 and the width of the aperture 208 being much greater than the diameter of the wires.

The frame plate I16 is in the form of an inverted rectangular tray and rests on an annular shoulder 209 formed on the upper edge of the table I15. The frame plate I16 may be turned relative to the table I15 and is held against lifting movement relative to the table I15 by means of holding bars 2I0, 2II extending into an annular groove 2I2 provided in the outer edge of the table H5 The holding bar 2I0 is supported on posts 2I3 secured by means of screws 2I4 to a sidewall 2I5 of the frame plate I16. The holds ing bar 2 is supported at one end on a post 2 I6 extending inwardly from the opposite side wall 2I1 of the frame plate I16 and on its other end has screw threaded engagement with a shouldered head adjusting screw 2I8, the shouldered head portion of which bears against the wall 2H and having the reduced end portion of the head journaled in an aperture in the wall 2I1. The holding bars 2I9 and .2 are machined out to fit the curvature of the groove 2I2 in the outer portion of the table I15. When the screw 2 I8 is tightened the frame plate I16 will be held in a required rotated position relative to the table I15 since the bar 2I I will be pressed against the base of the groove 2I2.

Two sets of positioning bands are provided to cooperatively form an adjustable frame for holding a crystal element in required position on the table I15. One set of bands comprises the bands 2I9226 and the other set the bands 22 I--222. The bands 2I9226 extend across the upper surfaces of the frame plate I16 and the table I15 from right to left and are adjustably held in required parallel spaced'relation. The bands 22I and 222 extend across the upper surfaces of the frame plate I16 and the table I15 from front to back and lie over the respective bands 2I9 and 226. Means are provided for separately adjusting each set of bands, the bands 2 I9 and 226 be ing adjustable by means of the manually operated knobs'223,224 and the bands 22I and 222 being adjustable by means of knobs 225 and 226. Since the bands and the means for adjusting them are identical in structure and arrangement the description of one set will'sufiice for an understanding of both. The band 2I6 is secured at one end to a rack 221 which is slidably supported on a sliding block 228 on which is also slidably supported a rack 229 to which an end of the band 220 is attached. The racks 221 and 229 are engaged by a pinion 236 on a rotatable shaft 23! and since each rack is on an opposite side of the pinion 236 and the knob 223 is mounted on the shaft 23I turning of the knob 223 will cause simultaneous movement of the bands 2I9 and 226 in opposite directions. A clockwise rotation of the knob 223 will bring the bands 2I9 and 223 toward the center of the table I15. The sliding block 228 and the racks 221 and 229 are located in a channel bar 232 the opposite side walls of which extend upward in frictional engagement with the block 229 and the racks 221 and 226. The channel bar 232 is supported on posts 233 by means of screws 234 and extends in parallel spaced relation with the side wall 2 I of the frame plate I16. A cover 235 is provided for the upper and the outer side portions of the channel bar 232, the cover 235 being supported in place by the screws 234 and having an elongated aperture 236 provided therein for accommodation of the shaft RI. The base portion of the channel bar 232 as shown in Fig. 24 is cut away at 231 to accommodate a tapped lug 238 which extends downward from the sliding block 226. The lug 238 is in screw threaded engagement with a male threaded shaft 239 which is journaled in a bearing 24!] supported in one end of the channel bar 232, the inner end of the shaft 233 being rotatably supported and retained against longitudinal movement in a portion of the base of the channel bar 232. When the knob 222 is turned the sliding block 228 is moved longitudinally within the channel bar 232 and this same mot-ion. is transmitted by means of the shaft MI, the pinion 236 and the racks 221 and 229 to the bands 2I9 and 226. It will be seen therefore that the bands H9 and 226 may be simultaneously moved toward or away from the center of the table I15 by operation of the knob 223 and that when the knob 224 is turned the bands 2I9 and 226 are simultaneously moved either backward or forward over the upper surface of the frame plate I16 and over the table I15. The bands 22I and 222 are provided with the same kind of operating means as the bands 2!!! and 226 and may be simultaneously moved toward or away from the center of the table I15 by turning the knob 225 and may be simultaneously moved, bothin the same direction, over the frame plate I16 and the table I15 by turning the knob 226. The bands 2I9, 220, 22I and 222 may therefore be moved to cooperatively embrace as shown in Fig. l the crystal I12 and will hold the crystal I12 in a required position on the table I15 while an end of the wire 51 is being solder-connected to the stripe I13 on the crystal. It will be seen that the bands 22I and 222 overlap the bands 2 I9 and 226 and that the free ends of the bands 22I and 222 are overlapped by an angle bar 24I which is secured to the rear portion of the frame plate I16 by means of the screws 242 shown in Fig. 20. The bands 2I9, 220, 22I and 222 are therefore prevented from jumping over the crystal. If in order to get the solder connection at some predetermined point off-center from the central portion of the stripe I 13 it is found necessary to slightly rotate the crystal from the position shown in Fig.1 this may be accomplished by loosening the screw 2I8 shown in Fig. 24 to release the pressure of the holding bar 2 against the table I15. The frame plate I16 may then be rotated relative to the table I15. This action will skew the crystal from the position shown in Fig. 1. The screw 2 I8 may then be tightened to hold the frame plate I16 and the crystal I12 in the new position. The aperture 268 in the table I15 is made wide enough to permit movement of the crystal to the new position without breaking or bending a wire secured to the under surface of the crystal I12. The table I15 as shown in Fig. 20 is calibrated at 243 and a mark is provided at 244 on the frame plate I16 to indicate the extent of rotation of the frame plate I16.

As shown in Fig. 2 a caster timer 245 is provided to control with time the application of heating current to the caster device 48. A solder timer 246 is provided to control with time the application of heating current to the point at which the wire is being solder-connected to the stripe I13 on the crystal I12. These timer devices may be of any conventional character and form suitable for controlling with time the application of the heating currents. The thermostat I91 controls theapplication of heating current to the heating elements I95 in the table I15. Suitable rheostats 241 and 243 are provided to control the strength of the currents applied to the respective caster device 48, and the point at which the solder connection is being made on the crystal, the rheostats being labeled Caster rheo. and Solder rheo. The switches 35 and 36 are provided for respective manual and automatic control of the duration of the current applied to the caster device. The switches 31 and 38 provide for respective manual and automatic control of the duration of the current applied to the point of; solder connection on the crystal.

Method of making solder connection The crystal I12 with the solder stripe I13 thereon is placed on the table I15 which is heated by means of the heating elements I95I95 supplied with current from a suitable source 249 over an obvious circuit. The heating current from the source 249 is automatically controlled by means of the thermostat I91 and a relay 259 which will be energized to open its contacts 25I and thus open the current supplying circuit when the contacts of the thermostat I91 close at a predetermined temperature.

The wire 51 is placed between the jaws of the chuck 49 and is extended through the aperture in the button H2. The chuck 49 is lifted and rotated to bring the projecting end of the wire 51 over the table I 15. The chuck 49 is then lowered to bring the bar 91 into engagement with the pin 94 and the Wheel 96 to hold the chuck in required position. The straps H9, 220, HI and 222 are moved by operation of the knobs 223 and 225 to engage the crystal I12 and bring the desired portion of the stripe I13 directly under the end of the wire 51. A suitable flux is applied to the end of the wire 51 and the fiuxed end of the wire is brought into engagement with the stripe I13 so that some of the flux on the wire will be deposited on the stripe I13.

The chuck 49 with the wire 51 therein is then lifted and rotated over the caster device 48 and is lowered to bring the bar 91 intoengagement with the pin 93' and the wheel 96 to hold the chuck in required position, the end of the wire 51 being thrust into the crucible II4 until the wire 51 touches the disc I38 which at the time serves as a bottom for the crucible. A screw 252 provided with a lock nut 253 is adjustably mounted on the slab 41 as shown in Fig. 12 to limit downward movement of the arm 59 to prevent undue thrusting of the end of the wire 51 into the crucible H4. The chuck is operated to hold the wire 51 so that a predetermined length of the wire will project below the button II2, the jaws of the chuck being operated to a closed position by means of the electromagnet 62 which is energized from the source of cur-- rent supply 1I when the switch 10 is closed. The chuck 49 is lifted and swung to the position shown in Fig. 1 and so that the end of the wire 59 is removed from the crucible H4.-

The caster device is operated to fill the crucible II4 with solder paste in the manner above described. The chuck 49 is lifted again and swung to a position over the crucible H4 and so that the end of the wire is thrust into the crucible, the depth of thrust being limited by the screw 252 against the under surface. of the arm 59. The crucible H4 is electrically heated by current supplied from the source H. For manual control of the duration of the heating current for the caster device 48 the switch 35 is operated. This closes the following circuit, source of current supply 1I, conductor 254, conductor 255, ammeter 39, conductor 256, conductor 251, contacts of switch 35, conductor 258, caster rheostat 241, conductor 259, electrode I58, leg I5I, leg I52, electrode I59, conductor 26D, conductor 26I, conductor 13 to source of current supply 1 I. The crucible is heated to a sufiiciently high temperature to melt the solder paste in the crucible H4. The reduced end portion II3 of the button H2 is pressed downwardly within the crucible II4 by the weight of the chuck 49 while the solder paste is being brought to a molten condition. The ring-shaped form of the crucible I I4 and the pressure of the button I I2 makes the solder take the form of the pellet I69 when the operating current for the caster device is shut off by opening of the switch 35. It will be seen therefore that a pellet I69 of solder of predetermined size and form is cast on the end of the wire 51. Automatic timing of the duration of the heating current may be obtained by closing the switch 36 instead of the switch 35.

The chuck 49 is lifted and rotated to bring the wire 51 with the solder pellet I69 cast thereon directly over the stripe I13 on the crystal I12 and the chuck is then lowered to bring the pellet I69 into engagement with the stripe I13. In this position the contact finger 14 touches the metal coating I14 or the stripe I13 on the crystal to close an electrosoldering circuit as follows: source of current supply 1I, conductor 254, conductor 255, ammeter 39, conductor 262, solder rheostat 248, conductor 263, contacts of switch 31, conductor 264, conductor 26I, conductor 11, arm 59 and jaws 60 and GI, wire 51, solder pellet I69, stripe I13, finger contact 14, conductor 265 to source of current supply 1I. Since the hot plate 50 comprising the table I15 is maintained at a temperature only slightly below the melting point of the solder in the pellet I69 the current applied through the point of engagement of the solder pellet I69 and the stripe I13 is sufficient to raise the temperature at this point of contact to a melting temperature for the solder. The material in the solder pellet I69 and in the stripe I13 is therefore sufficiently heated to make the parts fuse together. The current applied may be regulated by operation of the rheostat 248. If it 'is desired to automatically regulate the duration of the current supplied this may be accomplished by closing the switch 38 instead of the switch 31 the solder timer 246 then functioning to control the duration of the current supply. After the wire 51 is solder-connected to the stripe I13 on the crystal I12 the wire 51 is severed at a required point to leave a relatively small length of the wire extending from the crystal. This small length of wire may be used as a lead-in wire for the crystal and also as a supporting wire for the crystal. A similar wire may be electrosoldered to a stripe I13 on the opposite face of the crystal by the process above described. In this case the wire already soldered to the surface of the crystal extends into the aperture 208 in the table I15 while the crystal I12 is being adjusted to the required position and during the second soldering operation.

What is claimed is:

l. A wire holding chuck comprising a support, an arm pivotally mounted on said support, a pair of jaw members supported on said arm, means to operate said jaw members, an apertured button supported beneath said jaw members, supporting means for said button, a contact finger insulatingly supported on said arm and extending below said arm, and said jaws and said contact finger serving as spaced electrodes of an electrowelding system.

2. A wire holding chuck comprising a support, an arm pivotally mounted on said support, a fixed jaw member mounted on said arm, movable jaw member pivotally supported on said arm and movable relative to said fixed jaw member to hold said wire, an electromagnetic device mounted on said arm and mechanically connected to said movable jaw member for operation thereof, an apertured casing supported on said fixed jaw below said jaw members, said jaws and said contact finger being arranged to serve as spaced electrodes of an electrosoldering system, and means to supply current to said jaw members and said contact finger.

. ROBERT G. HUMPHREY. 

